Proposed research on the antigens induced by polyoma virus transformation during the coming year will include further experiments to define the specificity of antisera produced to the surface antigens of polyoma virus transformed mouse cells which have been used in the immunization of syngeneic animals. Following further characterization of the reactivities of such antisera we plan to use them in conjunction with studies aimed at preparation of soluble antigens from polyoma transformed cell followed by fractionation studies in an attempt to obtain information as to the molecular size and chemical nature of the detected antigens. We plan to examine any antiserum reactive fractions for tumor specific transplantation antigen activity as judged by the ability of such extracts to provide immunologic protection against subsequent doses of tumor cells. We will also be preparing antisera in preparation for detection of polyoma virus coded nuclear "T antigen" by an immunofluorescent technique for the monitoring of transformed cell lines.